Rice seeding rate differs with variety

Doreen Muzzi Farm Press Editorial Staff | Apr 12, 2002

A few years ago, most Delta rice producers planted all, or most, of their acreage in Lemont. That's no longer the case, and which variety you choose to plant in 2002 may determine how many seeds you put in the ground.

“We've planted 90 pounds of Lemont per acre for the last 15 years,” Mississippi Extension rice specialist Joe Street told growers attending this year's Delta Area spring rice meeting in Webb, Miss. “In 2002, 60 to 70 percent of the state's rice acreage will be in Cocodrie, and this change in varieties means that we've got to change the way we do business.”

Because of the varying seed sizes of the newer, more popular rice varieties, Street recommends growers plant seed based on the desired rate of seed per square foot rather than the previous standard of 90 pounds per acre.

“The seeding rates are going to be different for each variety because, for example, the seed size of Cocodrie is much smaller than Priscilla,” he says. “If you plant 90 pounds of Lemont, you're planting about 40 seeds per square foot. However, if you plant 90 pounds of Priscilla, you're planting only 34 seeds per square foot,” he says.

According to the Louisiana State University AgCenter, there are, on average, 20,734 seeds per pound of the rice variety Ahrent. In comparison, there are approximately 16,122 seeds in a pound of Priscilla, and 18,296 seeds in a pound of Cocodrie.

The LSU AgCenter is also getting away from offering its rice seeding recommendations in pounds per acre.

“Planting on the basis of seeds per acre to obtain the desired plant population is more accurate than planting pounds per acre. For example, 120 pounds of Bengal or Jefferson will contain fewer seeds than 120 pounds of Cypress or Cocodrie,” the LSU AgCenter's rice guide states. “Under typical conditions, about one-half of the seed survive to produce a plant, and an ideal plant population is approximately 10 to 15 plants per square foot.”

Street recommends planting 20 seeds per foot of drill row for 6-inch row spacing, 27 seeds for 8-inch row spacing, and 33 seeds for 10-inch row spacing. However, he says, “Growers may be able to produce a good crop with lower seeding rates.

“Our seeding rate studies at the Delta Research and Extension Center in Stoneville, Miss., have shown we can plant as little as 45 pounds of rice seed per acre before we start cutting yields,” he says. “I am comfortable with planting 30 seeds per square foot, but I am not yet ready to recommend planting 20 seeds per square foot except for hybrid rice.”

He adds, “We can make a crop on 10 to 15 plants per square foot. Because of this, we need to change our way of thinking and start thinking of seed per foot instead of seed per acre.”

“Regardless of the seeding system used, the desired plant stand is constant,” the LSU AgCenter's rice growing guide says. “Rice has the ability to tiller or stool. Several head-producing shoots can be formed from one plant. This is why a somewhat satisfactory stand can be produced from as few as six to eight seedlings per square foot if proper cultural practices are sued.

“Stands can be too thick as well as too thin. Excessively thick stands can often lead to more severe disease pressure as well as spindly plants that may be more susceptible to lodging.”

Adjusting the recommended seeding rates may be necessary depending on which type of seeding system is used. Growers who are either water-seeding or broadcast-seeding should increase their seeding rates to the equivalent of 100 to 150 pounds per acre, according to LSU guidelines.

Higher seeding rates may also be called for when planting conditions are less than ideal, when blackbird depredation is high, or when planting low germination seed.

Rice growers water-seeding into stale or no-till seedbeds with excessive vegetation, or where saltwater problems may cause stand establishment problems, should increase seeding rates to compensate for potential stand loss.